Wet Markets Offer Fresh Access to Seafood, But Are They Safer?

Posted in Our Blog on June 10, 2025

Wet markets are hugely popular in places around the world. When it comes to seafood, its popularity is even growing in the U.S. Keeping your seafood alive until you are ready for it implies that in addition to it being fresher, it is also safer. The two go hand in hand. Right?

A scientific paper published in International Journal of Food Microbiology by Chinese scientists unfortunately proves this theory wrong. These wet markets are very common in China, but the trend is growing across the globe. Even in the United States.

What exactly are wet markets and why are they just as vulnerable, if not more so than traditional processing facilities? Follow along to learn more!

What Are Wet Markets and How Are They Different from Fish Markets?

Wet markets are a bit different from fish markets. In the U.S., though, most of the time the terms are synonymous. However, across the world. Particularly in China where the study was conducted, it takes on a broader definition.

Wet markets are described as a commerce venue where live animals and fresh produce are available for sale to the public. It applies to all kinds of animals and freshly harvested produce.

For the purposes of this discussion, we will focus on seafood wet markets. As that is the topic of the paper. But it is safe to say that anywhere that there are people and food, there is a concern for food safety.

Purpose of the Research Paper on Seafood Wet Markets

The purpose of the paper, High Risk of Vibrio Pathogen and Antibiotic Resistance Transfer in Live Seafood Wet Markets of Shantou, China, researchers explored foodborne illness pathogens, antibiotic resistance, and the role biofilms play in this scenario.

Since Vibrio bacteria are a known risk in seafood fare, this pathogen was the primary focus. As biofilms are a certainty in this unchecked environment, the role this structure plays in antibiotic resistance and how it is exploited was also explored.

What’s a Biofilm?

A biofilm is a community of microbes forming a protective substance for them to live and grow. And infect.

It is one of the hardest disinfection hurdles to overcome because it is quite effective at aiding all types of methods of dissemination.

These sometimes-slimy complexes made up of “extracellular polymeric substances” allow the inhabitants (bacteria, fungi, protozoa, and yeasts) can form anywhere. They can coat surfaces, the animal, or free-float in the water if disturbed. The moist environment of wet markets is particularly vulnerable to this phenomenon.

This matrix shields potential pathogens from disinfectants, antimicrobial agents, and even desiccants designed to meet their germy demise.

It is an effective evolutionary move.

Serious Risk of Cross-Contamination in Wet Markets

Due to the proximity of live seafood to water and potential tank-to-tank transfer, cross-contamination in wet markets is a serious concern. The number of pathogens can grow to infectious numbers in biofilm.

Much like the concern for cross contamination within a deli counter we became acutely aware of during the recent deli meat Listeria outbreak, the transition from one tank to another to pull customer requests contributes to mobility from one food source to another.

Here’s What They Found

Scientists started by taking samples from live mantis shrimp and the surrounding water biofilm in the tanks they were in from various wet market vendors in Shantou, China.

• They found higher levels of antibiotic resistance genes in pathogens found in biofilms than in samples taken from shrimp samples.
• Vibrio species were discovered in both shrimp and biofilm samples. The genetic makeup of those samples showed significant resistance genes.
• The Vibrio samples obtained from the wet markets showed traits commonly linked to genomic flexibility and horizontal gene transfer. Something generally linked to the ability to reproduce antibiotic resistance genes.

Risk is Compounded by Incidence of Raw or Undercooked Seafood Consumption

In many cultures around the world, even in our own backyard, people eat seafood raw or undercooked.

I’m looking at you oyster lovers!

Consuming seafood that has not been properly heated to temperatures proven to kill harmful germs adds more risk to this already risky venue. Primarily because there has been a significant link between foodborne illness outbreaks and seafood pathogens like the Vibrio species of bacteria focused on in this study.

Adding in the strong linkage between wet markets and antibiotic resistance, and you have the makings of a serious threat to public health.

What’s the Solution?

Stating a problem is only half of the equation.

What is the solution?

The researchers do have ideas.

Educational Training

Knowing is half the battle, right? Educating those in the wet markets field is a likely first step in the right direction. Ensuring appropriate safe handling practices and disinfection techniques are deployed is difficult to achieve in countries without a robust health and safety system.

In the U.S., it comes down to increased inspection and consideration of biofilm activity in disinfection practices.

Promoting Fully Cooked Seafood Consumption

Heat is an effective tool. Regardless of biofilm production. Increasing awareness of the risks associated with raw seafood consumption and promoting fully cooked seafood instead is another move in the right direction.

People will do what people do, though.

More Research into Biofilm Disruption

Additional research is needed on effective disruption of biofilms. Removing the protective forces these microbes form will make existing disinfecting and sanitation efforts more effective.

What Are Your Thoughts on Wet Markets?

Have you ever bought seafood from wet markets?

I have. But honestly, I too never considered the additional risks. I do, however, always completely cook seafood.

Stay in Touch with Make Food Safe!

If you’d like to know more about food safety topics in the news, like “Wet Markets Offer Fresh Access to Seafood, But Are They Safer?,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!

By: Heather Van Tassell (contributing writer, non-lawyer)